1. Department of Fur-bearing Animal Breeding and Game Management, Faculty of Animal Bioengineering , University of Warmia and Mazury , Olsztyn , Poland
2. Department of Small Livestock Breeding , National Research Institute of Animal Production , 32-083 Balice n . Kraków , Poland
3. Division of Food Science, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences , Olsztyn , Poland